Stigmata are wounds or skin blotches which match the wounds suffered by Jesus during his trial and crucifixion. Some people believe that they can appear spontaneously through a miraculous act of God. But the evidence often points to natural causes, such as self-wounding or unusual medical conditions.

Some stigmata have unusual shapes, such as a cross or a circle, and a few even glow in the dark. Many of them also produce a pleasant perfume-like odor. In a few rare cases they aren't even visible, but are known to be present from the pain that they cause.

Because stigmata are counterparts to the wounds suffered by Christ, they are normally found on the hands and feet, on one side of the chest, and on the head, shoulders, and back. But they are not always real wounds, for many of them occur in the form of purplish skin blotches or tattoo-like markings. However, in a few cases, what looks like a blotch may actually be a real wound, because small amounts of blood will sometimes seep from it, even though no breaks are visible in the skin.

The word "stigmata" is the plural of the Greek word "stigma". This was an ancient name for marks that were pricked or branded onto the bodies of slaves and soldiers for identification purposes. The word was also applied to religious symbols tattooed onto members of pagan cults to show their devotion to particular gods and goddesses.

The first known use of the word with regard to the wounds of Christ occurs in Galatians 6:17, where the Apostle Paul says "I bear on my body the marks of Jesus." Biblical scholars aren't sure what kind of marks Paul was referring to. Possibly they were the result of wounds he'd received from scourgings and stonings by people who opposed his teaching. But another possibility is that he intentionally inflicted wounds on himself in an attempt to experience the same pain that Jesus felt.

Attempts to re-experience the suffering of Jesus definitely took place during the Middle Ages. Writings from that period contain many reports of mystics deliberately wounding themselves for such a purpose.

After self-wounding became common, people began to hear stories about wounds that appeared spontaneously. The most prominent case involved Saint Francis of Assisi, who died in 1226. It was said that his stigmata became present two years before his death, and that his hands actually appeared to have nails in them.

After Saint Francis died, other reports of spontaneous stigmata began to appear, and have continued to do so ever since. Near the end of the nineteenth century, an investigation by Dr. Antoine Imbert-Gourbeyre (1818-1912) identified hundreds of cases that had occurred up to that time. And the rate of occurrence seemed to increase during the twentieth century.

The best-known stigmatics of modern times include Padre Pio, Therese Neumann, Heather Woods, and Lilian Bernas, but there have been many others. In some modern cases, people have reported that they went into a trance in which they seemed to be nailed to a cross, and when they awoke they found the wounds or markings on their bodies.

Modern investigations indicate that stigmata can persist for different time periods, from a few hours to many years. They often appear suddenly, remain for a few days, then quickly fade away. In a few cases they have appeared on Good Friday and vanished on Easter morning.

Many Christians believe that the sudden appearance of stigmata is a supernatural sign that a person is very close to God. According to some reports, the miraculous nature of the wounds is verified by the fact that they don't respond to medical treatment, but can suddenly heal without treatment and without leaving any scars.

Some stigmatics say that they gladly suffer from the pain because their sacrifice helps pay for the sins of other people.

Stigmata are sometimes accompanied by other unusual phenomena such as powers of prophecy and the ability to live with very little food or water. St. Catherine of Siena (1347-1381) reportedly went without water for an entire month while her wounds were present. And Angela of Foligno (1250-1309) didn't eat anything for twelve years except for what was offered at the Eucharist. Other associated phenomena include visions, trance-like states, and tears of blood.

Many people doubt the claims about supernatural or miraculous causes for stigmata. One reason for this is that none of the reported miraculous occurrences has ever been documented by strict scientific methods. In addition, there may be natural explanations for all of the reported phenomena. Here are several possible explanations:

--- A person could inflict wounds on himself while in a state of religious ecstasy and not remember doing it afterward. Failure to remember a self-infliction could also occur if an alternate personality temporarily took control of a person's body and created the stigmata.

--- Another possibility is that intense prayer or deep meditation could bring about a psychosomatic reaction that causes the wounds or marks to appear. This process, sometimes called "psychogenic purpura", has been investigated medically, and there is some evidence that it can actually occur.

--- Some people have secretly wounded themselves in an attempt to get attention or look pious. One well-known example was Magdalena de la Cruz (1487–1560), who eventually admitted that her wounds were a hoax. In a modern case, carbolic acid was reportedly applied to the skin to create blister-like wounds. Another way to create fake stigmata is to paint them onto the skin, and several people have apparently used this method. The use of painted-on markings could explain cases in which the stigmata have unusual shapes, or glow in the dark, or appear to heal without leaving any scars.

Another reason for suspicion arises from questions about the locations of stigmata on a person's body. For example, many scholars doubt that Jesus even had any wounds on his hands. Available evidence indicates that the flesh of the hands isn't firm enough to hold a body on a cross, and that the nails were normally driven through the wrists instead.

Stigmata occasionally appear on individuals who aren't considered to be pious. One common explanation for such cases is that they are the work of the Devil.